One person died in violent anti-US protests across Pakistan Monday, forcing the army to deploy forces onto the streets and police to fire tear gas in efforts to quell the riots.

In the largest demonstrations, between 10,000 and 15,000 radical students and members of hard-line Islamic groups rioted in the western city of Quetta, burning down a police station, a United Nations building, three cinemas, a police station, a shopping plaza and a fire station.

Chanting "Down with America" and "Death to President Bush," the crowds smashed the windscreens of parked cars and threw stones at police.

As the violence intensified, police fired scores of tear gas canisters, repeated automatic weapons fire could be heard and army personnel carriers were deployed onto the streets.

Hospital officials reported one rioter died and eight other people were injured in the demonstrations which came despite a decision late Sunday by Quetta authorities to close the city's schools, colleges and universities for three days.

Police said they arrested 262 rioters in Quetta.

The protests came after the chief clerics of several mosques in Quetta reacted to Sunday's US-led military attacks on Taliban targets in Afghanistan by announcing over their public address systems that jihad (holy war) was now "mandatory" for Pakistani Muslims.

The anti-US sentiment of the protests swiftly took on a more general anti-foreigner tone, and as the demonstrators marched towards the Serena Hotel -- base for several hundred foreign journalists -- police had to fire more tear gas shells to keep the crowds away.

Another rally of 10,000 people was held at the border crossing of Chaman, around 100 kilometers northwest of Quetta.

The participants denounced Pakistan for backing the US and British strikes and burned effigies of President Pervez Musharraf before dispersing peacefully, witnesses said.

The decision to back the US war on terrorism in the wake of the September 11 attacks in New York and Washington has proved a delicate balancing act for the political leadership of Muslim Pakistan.

But Musharraf Monday defended Islamabad's support for the strikes -- after US planes over-flew Pakistani airspace -- saying it was in his country's national interests.

Police also had to fire tear gas in the northwestern city of Peshawar as they tried to disperse 1,500 slogan-shouting protestors.

The protestors, led mainly by Afghans, had gathered outside the Ahhaqina mosque in the Khyber Bazaar to denounce Washington's action and shouted: "Bush is a dog" and "Long live Osama".

The demonstrators, mostly supporters of the pro-Taliban Jamiat Ulema-i-Islam (JUI) party, pelted police with stones and pushed foreigners away from the city's mosques.

Dozens of police who initially stayed at a distance then intervened to disperse the demonstrators by firing tear gas.

In the capital Islamabad, another 1,500 students armed with canes and shouting anti-US slogans marched towards the American Center, which was cordoned off by a heavy police presence.

Similar protests were held in the southern city of Karachi and Lahore.

Following Monday's violence, the United Nations asked Pakistan's government to provide extra security for the organization’s staff.

UN spokesman Eric Falt said the request was made after rioters broke into and set alight the United Nations Children's Fund (UNICEF) office in Quetta, substantially damaging it. Five UNICEF vehicles and two motorcycles were also damaged.

The Pakistan government later expressed regret that UN offices were targeted in the violence and vowed to increase security to prevent further attacks.

"To prevent the reoccurrence of today's incidents, the government has tightened security arrangements around UN offices in Quetta and other cities of Pakistan," a foreign ministry statement said.

However organizers of Monday's protests said they had planned another "massive" rally for Friday in Quetta -- QUETTA, Pakistan (AFP)